Try this:

aggregate(x["VALUE"], list(substr(x[,"ID"], 1, 1)), sum)

On Thu, Jul 9, 2009 at 7:27 PM, Mark Na <mtb954@gmail.com> wrote:

> Dear R-helpers,
>
> I have two rows in my dataframe:
>
> ID    VALUE
> 1A    10
> 1B    15
>
> and I would like to combine these two rows into a single (new) row in my
> dataframe:
>
> ID    VALUE
> 1    25
>
> ...simply by specifying a new value for ID and summing the two VALUES.
>
> I have been trying to do this with with rbind, but it's not working.
>
> I'd appreciate any pointers.
>
> Thanks, Mark Na
>
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>
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>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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